To minimize effects on microclimates and human and wildlife habitats by reducing heat islands.
Have in place strategies to minimize the project’s overall contribution to heat island effects and that meet the following criterion:
|Area of Nonroof Measures||Area of High-Reflectance Roof||Area of Vegetated Roof||Total Site Paving Area||Total Roof Area|
Use any combination of the following strategies.
- Plants that provide shade over paving areas (including playgrounds) on the site. For newly installed plants, base shade area on 10-year canopy width at noon.
- Vegetated planters.
- Shade with structures covered by energy generation systems, such as solar thermal collectors, photovoltaics, and wind turbines.
- Shade with architectural devices or structures that have a three-year aged solar reflectance (SR) value of at least 0.28. If three-year aged value information is not available meet an initial SR of at least 0.33.
- Shade with vegetated structures.
- Paving materials with a three-year aged solar reflectance (SR) value of at least 0.28. If three-year aged value information is not available, meet an initial SR of at least 0.33.
- Open-grid pavement system (at least 50% unbound).
Table 1. Minimum solar reflectance index value, by roof slope
If newly installed, sufficient growing medium and plant material must be in place to provide full vegetative cover within 3-years.
Have in place a maintenance program that ensures all high-reflectance surfaces are cleaned at least annually to maintain good reflectance, all vegetation is maintained for plant health, and any vegetated structures or vegetated roofs are maintained for good structural condition.© Copyright U.S. Green Building Council, Inc. All rights reserved.